On this day in 1562, the now obscure but significant astronomer Christian Sorensen Lomborg, better known by his Latinized name Longomontanus, was born in the village of Lomborg in Jutland, Denmark. He was the son of a menial laborer who died when he was eight. But Longomontanus transcended his humble background, working at gritty jobs to put himself though school, where he showed a talent for the sciences. He eventually became the assistant of the more famous astronomer Tycho Brahe,whose observatory in Uraniburg was renowned as the finest and most advanced in Europe. As John Robert Christenson recounts in his book On Tycho’s Island: Tycho Brahe and his assistants, 1570-1601,the 26 year old Longomontanus was a bit long in the tooth to be an intern, but he was extremely bright conscientious and congenial, and his famous master took such a liking to him that Longomontanus became his personal secretary and even tutored his children.

Just as Peggy Olson really deserved credit on Mad Men for the concept that led to her boss Don Draper’s Cleo-winning TV commercial, Longomontanus helped to devise Brahe’scomplex model of the solar system, in which the Sun and Moon orbited the Earth, while the other planets in turn orbited the Sun. That ingenious, though incorrect, system accommodated planetary motion, without risking the displeasure of religious officials who had decreed the Earth to be the center of the cosmos. After Brahe’s death in 1610, Longomontanus became the keeper of his legacy, and in 1622 published the of Brahe’s system, the Astronomica Danica. Brahe also supervised the construction of an observatory in Copenhagen, but died before it was completed in 1647. Today, a Lunar crater bears his name.

And with that, here are the science and technology stories of the day.